Doctor Who 3.11: Utopia

( Big honking spoilers under here, trust me you don't want to peek if you haven't seen the episode yet )

As a warning, I've deliberately not watched the trailers for next week's episode or the Confidential. I'm determined to get to the final two episodes spoiler-free. Help me out, guys, by not spoiling in comments except if it's your own speculation in answer to some of the questions I raised. Thank you :-)